Right at the start of the video

Giving a pass on the shouldering issue since I always thought the butt stock to center mass or left shoulder thing was kind of an ehh thing since you're certainly sacrificing a stable shooting posture in favor of being more protected.
The dude loitering out of cover behind him though is an absolute tard thing though.

Shouldn't need much explanation. If guy on the left is firing at something that direction, and the guys on the right are slowly creeping around that corner from the other direction, someone is clearly in the wrong. Camera man is also not pulling security.

Camera Man finally pulls security! But it looks like grenade training isn't really a thing. First off, just chucking a grenade into a room doesn't insure everyone in that room is going to die. You normally follow up that by clearing into the room, but no one is stacked up here. This isn't an ALWAYS thing so not going to harp on it too much, but I'm going to guess that since Camera Man isn't dead, that grenade on the ground fell out of someone's kit.

More "who's pulling security and where?"

Going to guess someone peeped out and shot around that far corner no one was pulling proper security on, and they're alive only because arabs are shit at war rule is in effect.

... I have no words

Why is there a gaggle fuck here? Why is their automatic rifleman part of this gaggle fuck?
Pretty much everything after this is all after the situation is over.